1. Field of the Invention
This invention relates to applicators or dispensers which comprise crushable ampoules, preferably housed within flexible tubular containers. The invention also relates to methods of producing such applicators or dispensers.
2. Description of Related Art
Applicators comprising crushable glass ampoules housed within flexible applicator bodies are known in the art. Examples of such applicators comprise flexible tubular elements that have at least one end permanently closed. The other end can be frangibly closed or remain open to the environment. The crushable glass ampoules are typically sealed and contain a composition to be dispensed. Applicator tips are sometimes fixed to the open end to aid in the application of the composition contained within the ampoule. This type of applicator is useful for multiple applications including use as air fresheners, use in dye marking, and use in pregnancy test kits, as well as for dispensing medical solutions, dental products, health and beauty aids, adhesives, and other compositions. To use the dispenser, the flexible applicator tube is squeezed at the area where the glass ampoule is located. Sufficient force is applied by a user""s fingers to break the glass ampoule, releasing the composition contained within. The composition is then applied through, or otherwise allowed to exit, the open end (i.e., the end with the applicator tip).
One drawback to such applicators is the possibility of a glass shard from the broken ampoule piercing the flexible tube and entering the user""s hand during crushing and dispensing. Upon crushing of the glass ampoule, multiple small sharp glass shards are created. Among the glass shards created during breakage of the glass, shards having a length sufficient to transect the flexible applicator tube are created. A certain percentage of these shards become reoriented such that they are perpendicular to the length of the applicator tube (i.e., with their longitudinal axis oriented toward the user""s finger(s)). The force applied during crushing and dispensing can be sufficient to force at least some of these reoriented shards through the flexible tube and into the user""s finger(s).
This disadvantage is overcome in some applicators by a cardboard overcap that can be placed around the applicator body to protect the user""s fingers during crushing of the ampoule. Such an applicator, consisting of a glass ampoule, a plastic butyrate tube, and a cardboard overcap, is sold by the James Alexander Corporation of Blairstown, N.J. In operation, prior to crushing of the ampoule, the cardboard sleeve is slid over the ampoule and the user crushes the ampoule by squeezing the ampoule with the user""s fingers through the cardboard sleeve. However, this solution does not eliminate the production of reoriented glass shards, and is subject to a certain failure rate due to the reoriented shards puncturing the overcap along with the flexible tube. It also requires a separate part that makes the dispenser a two-handed operation to place the cardboard cover on the applicator. Moreover, as the sleeve is opaque, one cannot see whether the ampoule has been properly crushed during use without removal of the sleeve.
Commonly assigned U.S. Pat. No. 5,928,611 (previously published under PCT Application No. WO 96/40797), the disclosure of which is hereby incorporated in its entirety, discloses an applicator for dispensing polymerizable or cross-linkable monomer compositions. The applicator comprises an applicator body that holds a crushable ampoule. The crushable ampoule contains the monomer composition that is to be dispensed. The applicator can further comprise an applicator tip. This applicator, like those described above, does not disclose means to avoid reorientation of glass shards.
Other methods for protecting a user""s hands during crushing of a glass ampoule are disclosed in U.S. Pat. No. 5,690,958 to McGrath. McGrath discloses a unit dose applicator for dispensing chlorhexadine gluconate (CHG). The applicator may be an elongated cylindrical glass vial or ampoule that is housed within an elongated cylindrical, flexible, synthetic resin cover of a size to fully encase the vial. A porous applicator swab is fitted within one end of the applicator cover, and extends outward therefrom. The cover is disclosed as being a protective cover that protects the user""s hand from glass shards created during crushing of the unit dose glass container. However, McGrath does not disclose or claim the use of his applicator to dispense anything except CHG and has the disadvantage that reoriented glass shards can puncture the protective resin cover.
U.S. Pat. No. 4,826,025 to Abiko et al. discloses an ampoule package that is designed to be precisely cut at a constriction between upper and lower sections of the package. A heat-shrink film is provided over the constriction part to prevent scatter of fine particles of glass formed by the cutting of the constriction. Such an ampoule is not designed to be crushed by a user""s fingers. Thus Abiko is not concerned with problems of reoriented glass shards that could puncture a user""s fingers during the crushing.
Similarly, it is known to coat glass bottles with coating materials to improve resistance to breaking. For example, U.S. Pat. Nos. 3,877,969, 3,889,013, and 4,099,638 to Tatsumi et al. disclose coating the surface of glass bottles with two different kinds of coating materials in a specific sequence. The coating materials include an olefin copolymer containing OH and/or COOH groups in its molecule. The coating also includes a polyisocyanate or a mixture of a polyisocyanate and a polyol or a thermoplastic polyurethane. These methods are not disclosed as having applicability to, and in fact are conceptually opposed to, glass containers that are designed to be broken, such as glass ampoules broken by finger pressure. Rather, they are intended to resist or prevent breakage.
Thus, there is a need for an applicator comprising a crushable ampoule that can be used without fear of puncture of the skin during crushing. The present invention satisfies that need by providing a protective barrier material over the surface of the crushable ampoule. The protective barrier material not only protects a user""s hand from puncture with shards created during crushing of the ampoule, but it can be used and incorporated in an applicator in a convenient and economical manner.
The invention provides an applicator or dispenser, which comprises a crushable ampoule, containing a composition to be dispensed, that is covered or coated by a resistant barrier material. The applicator can further comprise a hollow applicator body made of a flexible and deformable material. The applicator body is of a generally tubular shape, having an end that is permanently closed and another end that can either be closed (sealed) or open to the environment. At least one crushable ampoule is contained within the lumen of the applicator body. Each crushable ampoule is sealed and can contain a composition that is to be delivered or applied to a site or reacted with another material in the applicator. Disposed over a surface of each crushable ampoule is a material that acts as a barrier against formation of reoriented glass shards upon crushing of the ampoule. The barrier material can be applied to either or both of the interior or exterior surface of the crushable ampoule, applied between the ampoule and applicator body, and/or applied to the exterior of the applicator body. It may be applied to the entire interior and/or exterior surface, or may be applied only to a selected portion of such surface. In the latter case, it is preferably applied to a portion, such as a central portion, that is most susceptible to crushing and shard reorientation.
According to one aspect of the invention, the barrier material protects a container body, and thus a user""s fingers, from puncture by reoriented glass shards during crushing of the ampoule by the barrier material being in contact with both the flexible tube of the applicator body and the crushable ampoule. The contact may be through affixing of the barrier material to the ampoule or by adhesive contact.
According to another aspect of the invention, the barrier material is in contact with an interior surface of the ampoule. Again, the contact may be through affixing or adhering of the barrier material to the ampoule.
According to a further aspect of the invention, the barrier material may be a resistant polymeric layer, such as a MYLAR(copyright) polyester film, affixed to the exterior of the ampoule or applicator body.
According to yet another aspect of the invention, the barrier material may be the combination of an adhesive layer and a label adhered to an exterior surface of the applicator body.
According to yet a further aspect of the invention, the barrier material may be a plastic composition coated on the exterior of the ampoule or applicator body.
According to each of the above-described aspects, the barrier material is thin enough and/or flexible enough to allow crushing of the ampoule by an average person""s finger pressure.
The invention also provides a method of making an applicator or dispenser. The method comprises applying a barrier material to a surface of one of the crushable ampoule and the applicator body. The method can further comprise inserting the coated crushable ampoule into the applicator body.
Alternatively, the method may include insertion of the barrier material onto an interior surface of the applicator body before insertion of the ampoule within a lumen of the applicator body. Upon insertion of the ampoule, the barrier material is spread over a substantial surface of the ampoule to provide resistance to reorientation and/or puncture by glass shards.
The method may also include application of a barrier material to the exterior surface of the ampoule before insertion of the ampoule within the lumen of the container body.
The barrier material may be an adhesive that is coextruded with the flexible material making up the applicator body.
When the barrier material is adhered to a surface of the crushable ampoule, the number of reoriented shards generated during crushing of the ampoule can be reduced or eliminated. Thus few, if any, reoriented shards that can transect the applicator and puncture the user""s skin are created. This is because the shards, when created, are trapped by the adhered barrier material in the orientation in which they were created. In this manner, puncturing of the user""s fingers by reoriented shards is reduced or eliminated, and the safety of the applicator is improved. Furthermore, because a wide variety of barrier materials can be used, which are generally inexpensive, the barrier material can be incorporated without a significant increase in the cost of producing the applicator. In addition, the applicator can be used in a single, one-handed operation, and does not inhibit the view of the applicator. Moreover, when the barrier material is affixed or adhered in place, there is no possibility that the sleeve may slide from a desired area to be protected.
Thus, in some embodiments, the barrier material may form a layer or coating that is affixed to or adheres tightly to the material from which the ampoule is made. During crushing of the ampoule, the barrier material in these embodiments continue to be affixed to or adhered to the material of the ampoule, and, to a great extent, to itself. Thus, the three dimensional structure of the barrier material is not completely destroyed during the crushing process. In other words, although the ampoule is crushed, the general shape of the ampoule is retained by the barrier material on the ampoule. Because the barrier material remains affixed or adhered to the shards of the ampoule and generally retains its original shape, the production of reoriented shards is greatly reduced. Furthermore, at least one area of the ampoule is preferably left uncovered so that the composition within the ampoule can escape upon crushing of the ampoule. The uncovered area can be provided as one relatively large area, for example at one end of the ampoule, or can be provided as many relatively small areas dispersed over a specific area or over the entire ampoule. The uncovered area can be any shape or size as long as the protective function of the barrier material is not compromised.
It is often preferable for the barrier material to have adhesive properties so that it can be directly adhered to the material comprising the ampoule. If the barrier material is not adhered to (or sufficiently affixed to) this ampoule material, then, upon crushing of the ampoule, reorientation of shards can occur because they are not trapped in their original orientation. In embodiments where the barrier material is an adhesive, the adhesive material itself does not provide a sufficient physical barrier to the shards, as it is easily punctured by reoriented shards. It is the substantial blocking of reorientation of the shards by the adhesive in these embodiments that provides the protective function of the present invention.
In other aspects of the invention, the barrier material may be affixed to the ampoule and serve to partially prevent reorientation and may also be formed of a material that provides a physical barrier to penetration by shards of glass.
Further, when the barrier material is applied to the exterior surface of the ampoule, entrapment of the shards by the barrier material provides an added level of protection by providing a barrier against shards that failed to be adhered by the barrier material. For example, during crushing, a certain, although small, portion of the shards will not be adhered to by the adhesive barrier material. This is especially true for shards that are created solely from ampoule material at surfaces not covered by the adhesive barrier material. A certain percentage of these free shards can become reoriented. However, the shards entrapped by the adhesive form a relatively thick, strong layer that can stop the reoriented shards from passing through and into the user""s fingers. Thus, the shards themselves provide added protection and serve as a protective physical barrier in such embodiment, allowing the use of an adhesive with weak physical barrier properties.
The applicator body can hold one crushable ampoule containing a composition to be dispensed and/or reacted, or can contain multiple crushable ampoules, each containing a composition to be dispensed and/or reacted. When the applicator comprises multiple ampoules, each ampoule can hold either the same composition or a different composition. Included is the situation where multiple ampoules contain the same composition while other ampoules contain different composition(s). For example, the applicator can comprise two crushable ampoules. The first ampoule holds the first part of a two-part adhesive and the second ampoule holds the second part of a two-part adhesive, such as a two-part epoxy adhesive. Furthermore, in embodiments where multiple ampoules are included, at least one ampoule can be contained within another.
Although the invention is further described with respect to preferred applicators comprising an applicator body that contains a coated crushable glass ampoule, the invention also encompasses applicators comprising the adhesive-coated ampoule alone.